Stripping means for pressure rolls



H. HINCKLEY.

STRIPPING MEANS FOR PRESSURE ROLLS. APPLICATION FILED ocr. 26. 192|.

. ,430, 1 .66 -Patf'enned Sept. 26, 1922.

/N VENTO/3 Patented Sept. 25,' i922.

.HAROLD Irrivoxniir,

or randen, MAINE'.

' sfrnirrrne ivrnelns ronrnnssunn norms.'

Animation ined october ze, 1921.` 4 seriai No. 510,449.

e To all whom t may concern.'

Beit known that l, HAROLD HINQKLEYp f residing at Bangor, inthe county lof Penobf scot, State of Maine, have inventedl certain 5 new and useful Improvements in Stripping* Means for Pressure Rolls;y and I do hereby declare the following to be a full, clear, and

fexact description of the inventiom'such aS willenable others skilled inthe art to which' itappertains to make and use the samelf In the manufacture' of paper, the water is removed-from the web in two stages. First,

the web, supported on porous elts, is passed between successive' pressure rolls and over suction boxes, and as much water as practi#` cable is sucked and squeezed from it. ln the7 second stage the web is run over' A'and around a battery of steamdieated drying rolls `and thus reduced to substantial dryness. In the zofmanufacture of pulp vin a wet machine this inal drying stage is not economically -easi-.

" ble because of the oheapness or" the product.

' and the thickness oic the pulp sheets. For this reason'all of the water which isffre-l 1- much as possible) must be mechanically ex# pressed. This hasfmeant increasing ythe pressure exerted by the pressure rolls to a maximum. Where the pulp is carried bevv3,0l tweentlie rolls supported upon a telt, the

maximum pressure is limitedto that pres# Vsure which'thefelt can/stand. n; pressure highenough to be eliicientirom a dewatere' ying standpoint ywould ruin thefelt in a shorti time.

In' accordance with the rece-nt invention of 'HarryE Tidinarsh,`patented'in U.' S.' Patent y-No 1,387,954`August 16,' `1921, the pulp sheets are passed through thein'al pressure discovered that by properly corrugating the surfaces of these rollsthey would bite the pulp and carry it' through, contacting only with the bare rolls-themselves it thereforer` becomes possible to increase' the pressure and' K sure? It 'has been" discovered that as the pressure is increased beyond 'a' certain point" the pulp" is "forced within'thecorrugations on the surface of the rolls, especially the line pieces ofy pulp which'result when the web is separated transversely into sheets.l rl`his `moved `(and it is desirable t0 remove as rolls Aunsupported by the telt, he having f and Fig. 2- is .forced'outofvposition and the entire sheet 0r part of it follows the rolls and passes between it andthe doctor. f TWhere the upper roll is offset in the direction trom which the'pulp approaches, this ditliculty is experienced, `particularly in connection' with that roll.

; 'tlf `this difficulty could bey eliminated, greater ypressure could be exerted by the final pressure `rolls'and the eiiiciency of the -wet ma-' chine increased accordingly. It is `therefore an object ot this present invention to overcome this difficulty, and devise means which shall prevent the pulp from adheringto and yfollowing the pressure rolls, even where excessive pressures are employed. f

This object has been accomplished by pro-r l'vidi'ng they pressureroll tof which the pulp tends to adhere, with a number of narrow circumterential grooves, and mounting guidesk kwithin these ygrooves which extend tangentiallybeyond thepoint of contacter1 the roll 'in question with its mate. A series of :endless belts running loosely within these grooves and around an idler roll beyond and in the direction ofy travel of the sheets have been found to serve well as these guides.

The orooves are so narrow asv not materially toisubtract yfrom the pressing area of the roll and deep enough -sothat the pulp is not forcedy Iaround the guides. 'As' the` sheet emerges from the vnap of the rollsit is forced forward4 by the guidesy and cannot follow the roll.

The inven'tionwilllbeiniore clearly understood after a study of the accompanying l dra'wing,vwhich discloses onepreterred embodiment of it, although it is clear that other structural details might be employed without l(lr-parting from the lspirit of the invention. In these drawings Fig.' lis aside elevation of the iinal bare pressure rolls of a wet machine equipped with a stripping device in accordance with this invention, a plan view o'f these rolls and the stripping device.

`The -rame l in ygeneral by the reference numeral l.y On this frame are mounted upper and lower corrugated pressurerolls 2 and 3 respectively, the upper yroll being odset slightly in a direction toward which kthe sheet approaches.

'of the machine is indicatedy The upper roll 2 is pivotally mounted about bearings 4 and is positively forced against the lower roll 3 by means of a weight 5 acting through compound levers 6, 7 and 8 and rods 9. The pressure can be varied by movement of the weight 5. The pulp sheets 11 are fed between the pressure rolls by means of a felt 12 passing over rollers 13. A table 1a is provided which serves to guide the'pulp between the rolls, but this table may or may not be used, depending upon the stiffness of the pulp. The far side of the lower roll is provided with an adjustable doctor 1() which keeps this roll clean and is adequate to prevent the pulp from adhering to it. rI`he foregoing structure is all old and is clearly disclosed in the patent to Tidmarsh discussed above.

In accordance with the present invention the upper roll 2 is provided with a Vplurality of grooves 15. Beyond the pressure rolls and adj ustably mounted upon the frame of the machine is an idler roll 16. Running around this idler roll and seated within the grooves l5 area plurality ofendless belts 17. These belts are preferably very narrow, ropey (cod line) one-eighth of an inch in diameter having been successfully employed, and the grooves 15 are wide enough only to accommodate these verynarrow belts. The wider the belt and the grooves the greater the amount of pressing area which is lost. The grooves are deep enough to permit the belts 17 to run loosely and not be subjected to pressure when the pulp is passingbetween the rolls. The

belts may to advantage be narrow chain belts. Y

The operation of the device will be clear from the foregoing, but may be briefly reviewed as follows. As the pulp sheets emerge from the nap of the rolls they are in contact with the endless belts 17 and forced away from contact with kthe upper roll. Hence, any tendency which vthe pulp may haveto adhere to and follow this roll is counterafted and the sheet is fed forward ontothe off-bearing belt which is not shown.

rIbis invention has made possible the use of greater pressure than could heretofore be employed. ,It is simple in its operation, "ccs not materially detract from the pressing etlicieficjv of the rolls and makes .it impossible for the pulp to adhere to and follow the upper roll. Although it has been found that in most instances only the upper roll lcauses trouble, yet it is clear that these lguides could be employed in connection with either or both rolls should the pulp evince a tendency to adhere to either. The use of endless belts has also been found to answer the requirements, but it is possible that stationary guides might be employed, and under some circumstances might vbe desirable. vention is therefore in no sense limited to The inthe exact form of guides shown and described.

I claim: l

1. In a wet machine, the combination of a pair of pressure rolls, a circumferential groove in the face of one of the rolls, and a guide in said groove at the point where the two rolls contact, said guide extending tangential-ly beyond the rolls.

2. In a wet machine, the combination of a pair of pressure rolls, a circumferential groove in the face of one of the rolls,and a guide in said groove, said guide extending beyond the rolls and serving to prevent the sheets passing between the rolls from adher-` ing to `that roll.

3. Ina wet machine, the combination .of a pair of bare corrugated pressure rolls, a plurality of circumferential grooves in the face of one of the rolls, `and guides in said grooves at the point where the two rolls contact, said guides extending beyond the rolls andl serving to prevent the sheets passing between the rolls from adhering to that ro 1l. In a wet machine, the combinationof upper and lower pressure rolls, the upper roll being somewhat in advance ofthe lower, circumferential grooves in .the face of the upper roll, and guides in said grooves at the point where the two rolls contact, said guides extending` beyond the rolls and serving to prevent the sheets passing between the rolls from adhering to that roll.

5. In a wet machine, the combination -of a pair of pressure rolls, circumferential grooves in the face of one of the rolls, and endless belts in said grooves extending between the rolls andserving to prevent sheets passing between the rolls fromy adhering to that roll. A

6. In a wet machine, the combination of upper and lower pressure rolls, the upper roll being somewhat in advance of the lower, circumferential grooves in the face of the upper roll, and endlessbelts in said grooves extending beyond the rolls and serving to prevent sheets passing between the rolls from adhering to that roll.

7. In a wet machine, the combination of upper and lower pressure rolls, the upper roll being somewhat in advance of the lower, a plurality of narrow circumferential grooves in the face of the upper roll, narrow endless belts in said grooves passing between the two rolls and extending beyond to prevent sheets passing between the rolls from adhering to that roll, the grooves being deeper than the thickness ,of the endless belts.

- 8. In a wet machine.y the `combination of a pair of pressure rolls, circumferential grooves in the face of one of the rolls,y an idler roll vbeyond the pressure rolls, and endless belts passing around the idler, roll and in the said grooves in the pressure roll and serving to prevent sheets passing between roll, an idler roll between the pressure rolls, the rolls from adhering to that roll. and endless belts passing around the idler 9. In a wet machine, the combination of roll and in the said grooves in the pressure l0 upper and lower corrugated pressure rolls, roll and serving to prevent sheets passing 5 the upper roll being somewhat in advance between the rolls from adhering to that roll. f of the lower, a plurality of narrow ciroum- In testimony whereof aliX my signature. ferential grooves in the face of the upper HAROLD HINCKLEY. 

